Urethane or Hypalon for tubes?

sunrider · 16 June 2005, 02:25

The link below is to a report made in 1993 by the US Navy comparing the benefits of Urethane versus Hypalon coated fabric for use in RIBs. Does anyone know of more current research or information on the subject, or discussion of other types of fabric? In particular, I would like to learn what research has shown to be the best material to use in a high UV location such as Hawaii.

http://www.wing.com/PUvHYPE%204.13.05.pdf

boatster · 16 June 2005, 04:18

Thinking of retubing some more Willard ribs?

Very interesting read btw, thanks for that. So when they state "urethane coated fabrics" do they mean the pvc material that boats at West Marine and Zodiac sell as tenders? It seems, according to this document the urethane coated fabrics are much better suited for ribs. Or am I getting urethane as in polyurethane mixed up with pvc ?

I wonder how the military determines when a tubeset is worn out. The document says the British Military replace every 8 years. My Avon sr4 is roughly 14 years old. I doubt they replaced the tubes during its life. How would you know it was going bad? They don't leak air and all the seams are still good. Seems good to me.

boatster · 16 June 2005, 18:39

BTW Sunrider,

Did you see those 2 Willards in HI that are up for auction?

codprawn · 16 June 2005, 19:00

Having seen Avon's still going strong after 20 yrs of REAL abuse I find it strange anyone could want anything other than Hypalon!!!

limeydal · 16 June 2005, 23:09

where do you get the links for the HI auction??
Would like to check them out;
cheers Dal

boatster · 16 June 2005, 23:21

Just promise you won't bid against me if a rib pops up in California

http://cgi.govliquidation.com/auction/view?id=616509

sunrider · 16 June 2005, 23:33

Yes boatster, I saw the Willards in Hawaii. I bought one on the previous auction there and the current ones are similar, but may not be in as good condition. I'm getting some current prices on tube sets, but don't think I will need one for the Willard I already have..but perhaps one of the others. It may be as easy for me to work on a couple of them as on one while I'm in the islands so will be watching the bids. About the fabric...I'm told that the west marine and zodiac non-hypalon boats are usually made from Strongan, a proprietary coated fabric developed by Zodiac. Others may have more accurate information though. I believe the pvc boats are straight pvc, and the urethane products are coated fabric...but others will know more than I on that subject as well and I hope we hear from them on this forum.

Limeydal, they are being auctioned by the government - there are multiple sites that post boats for auction by the government (at every level) and you can find the entire list easily via Google.

codprawn, I'm with you on being very satisfied with hypalon. that's why this research was so interesting to me - it seems to favor urethane. My experience with Hypalon has been great. My primary RIB has been in the unprotected sun, and all oceans, since 1991. The tubes are oxidized but still hold air well. I've contacted the Navy to see if they have any updates to this research and will post any results I come across.

boatster · 17 June 2005, 01:47

Sunrider,

The urethane seems to win in the manufacture, weight, and strength dept according to that article. Very compelling argument, but with such a good reputation for hypalon only time or a good weathering test can determine how Urethane materials hold up. I can't imagine that someone hasn't already made a better material with all the technology we have today. Aren't the USCG & military going towards those SAFE boat foam collard boats anyways?

codprawn · 17 June 2005, 02:43

Better technology today??? NOT always the case - for example most paints these days are not as good as the oldies - becuase of environmental reasons - the same with antifoulings.

Look at guns - modern technology hasn't really come up with a better way of killing people on a man to man basis - the Browning 0.5" machine gun is still in use - first came out in 1921!!!

Then you have jet engines - more fuel efficient and quieter BUT speeds have dropped since the 60s.

So just becuase it is newer doesn't ALWAYS mean better!!!

prairie tuber · 17 June 2005, 04:51

I did some research into this a year or so ago, and came to the conclusion that while polyurethane may have better abrasion resistance than hypalon, it will deteriorate (as will PVC/strongan - same thing) far more rapidly than hypalon will, especially with UV exposure. Additionally polyurethane & PVC are much more difficult for DIY repairs, usually the tubes need to be repaired by the manufacturers.

Zodiac's pleasure boats went to PVC (strongan) for the main reason of reducing productions costs. Their are some applications, where things can be done with PVC that can't be done with hypalon (such as air floors). As for Zodiac's Professional & Military boats, all but one (the gs 380 with air floor) use hypalon rather than PVC. Again the cost of those hypalon boats is far greater than their PVC counterparts. For example, if you look at Zodiac's military futura commando 470 (probably zodiacs most famous craft), it will easily cost double what the PVC Futura Mark III would cost.

For me, I would only consider hypalon if I am spending several thousands of dollars on a boat.

swginn · 17 June 2005, 11:52

Quote:

Originally Posted by boatster

The urethane seems to win in the manufacture, weight, and strength dept according to that article. Very compelling argument, but with such a good reputation for hypalon only time or a good weathering test can determine how Urethane materials hold up.

Well they're are some companies out there that do use PU (polyurethane) for tube manufacture, mainly Tornado and XS-Ribs so a good weathering test would be to simply find an old Tornado and compare it to a similarly ageed hypalon RIB. You'll find that the PU tubes won't have faded as much and have kept their lustre. One thing I always notice about old Tornados is that I always get their age wrong because the tubes always look 4/5yrs newer.

Has been discussed many a time here before, see here:
http://www.rib.net/forum/search.php?...0&pp=25&page=2

Be aware that in a lot of these threads PU (polyurethane) has been confused with PVC (Poly Vinyl Chloride). PVC is actually more closely related to Polyethylene, and therefore Hypalon than PU.

The only similarity is that both fabrics can be heat welded. PVC is an unstable polymer because of the chemical make up of the fabrics coating.
This means that the PVC fabric is constantly changing, oxidizing and migrating to the surface. PVC's are liquefied with solvents where polyurethane is liquefied by heat, leading to a significantly more stable fabric coating. Stories about tubes rotting in the sun are about PVC - not polyurethane.

http://www.wing.com/polyurethane.html

prairie tuber · 19 June 2005, 05:55

Here is a link to a previous thread on this topic;

http://www.rib.net/forum/showthread....5&page=2&pp=10

In that thread Paul Tilley (who is one the foremost rib retubers anywhere) had this to say about the different tube fabrics:

"Hypalon is considered to be the best fabric for tubes due to its good all round properties ,it can give a very long life ,the oldest tube i have seen was 26yrs old and used regularly before needing retubing ihave never seen a PU or PVC tube last any where near that long , some pvc and pu tubes have been known to last less than 18 months .PVC and PU are both harder to glue than hypalon thus making them less user friendly when you need to do that little get you home repair .IT is also afact that in the uk especially most RIB builders are only relatively small and it would not be cost effective to buy the sort of equipment Tornado have to make their very nice looking welded PU tubes as most glued PU tubes seem to fall apart when the glue seems to crystalize . In my humble opinion the only thing PU has going for it is its better abrasion resistance but this is outweighed by the user friendlyness of hypalon . The UK MOD tried PU tubes but seem to be sticking to hypalon."

When it comes to tubing materials, Paul Tilley is as knowledgeable as they come.

jyasaki · 21 June 2005, 22:08

The US Navy appears to disagree with Mr. Tilley:

http://www.wing.com/PUvHYPE%204.13.05.pdf

jky

prairie tuber · 22 June 2005, 02:52

Quote:

Originally Posted by jyasaki

The US Navy appears to disagree with Mr. Tilley:

http://www.wing.com/PUvHYPE%204.13.05.pdf

jky

There is a parallel discussion about tubing fabrics and that document in the "DUX inflatable boats" thread (also currently on page 1 of this forum's listings). It's worth having a look at.

codprawn · 22 June 2005, 13:11

Quote:

Originally Posted by jyasaki

The US Navy appears to disagree with Mr. Tilley:

http://www.wing.com/PUvHYPE%204.13.05.pdf

jky

Yah what do they know??? Just ask Avon inflatables - probably the pioneer of the RIB - they have been building them for years - they still use hypalon whilst their now sister company Zodiac use the other stuff - Avon STILL refuse to use the stuff!!!

swginn · 22 June 2005, 15:19

Quote:

Originally Posted by codprawn

Yah what do they know??? Just ask Avon inflatables - probably the pioneer of the RIB - they have been building them for years - they still use hypalon whilst their now sister company Zodiac use the other stuff - Avon STILL refuse to use the stuff!!!

Wrong again!!

I assume by "other stuff" you mean PU as you referred to the Mil report on PU.

Zodiac actually don't use PU, they use what they call "Strongan Duotex" which is just a fancy name for an evolved, improved PVC and as I said before PVC is actually more closely related to Polyethylene, and therefore Hypalon than PU.

This is one of those 2 vs 4 stroke debates that really doesn't have any right answer. But at least people know the difference between the two. Try not to confuse PVC and all of its fancy derivatives (Strongan Duotex, Akron, etc.)with PU (polyurethane) and Hypalon.

IMHO the reason for all the fancy names is that manufacturers want to disguise the fact that their boats use PVC which is much inferior to both Hypalon and PU.

codprawn · 22 June 2005, 15:26

Quote:

Originally Posted by swginn

Wrong again!!

I assume by "other stuff" you mean PU as you referred to the Mil report on PU.

Zodiac actually don't use PU, they use what they call "Strongan Duotex" which is just a fancy name for an evolved, improved PVC and as I said before PVC is actually more closely related to Polyethylene, and therefore Hypalon than PU.

This is one of those 2 vs 4 stroke debates that really doesn't have any right answer. But at least people know the difference between the two. Try not to confuse PVC and all of its fancy derivatives (Strongan Duotex, Akron, etc.)with PU (polyurethane) and Hypalon.

IMHO the reason for all the fancy names is that manufacturers want to disguise the fact that their boats use PVC which is much inferior to both Hypalon and PU.

Actually I meant PVC - haven't read the report for a long time!!! Yes I DO know the difference!!!

prairie tuber · 22 June 2005, 15:44

Quote:

Originally Posted by swginn

Wrong again!!

I assume by "other stuff" you mean PU as you referred to the Mil report on PU.

Zodiac actually don't use PU, they use what they call "Strongan Duotex" which is just a fancy name for an evolved, improved PVC and as I said before PVC is actually more closely related to Polyethylene, and therefore Hypalon than PU.

This is one of those 2 vs 4 stroke debates that really doesn't have any right answer. But at least people know the difference between the two. Try not to confuse PVC and all of its fancy derivatives (Strongan Duotex, Akron, etc.)with PU (polyurethane) and Hypalon.

IMHO the reason for all the fancy names is that manufacturers want to disguise the fact that their boats use PVC which is much inferior to both Hypalon and PU.

Agreed.